1. Field of the Invention
The present invention relates to an infrared reflective patterned product and particularly relates to an infrared reflective patterned product in which the ratio of the reflectance of an infrared reflective pattern portion at a wavelength with the highest reflectance in an infrared region of 780 nm to 2500 nm to the reflectance of a non-pattern portion is large in a case where the infrared reflective pattern portion is obliquely irradiated with infrared rays.
2. Description of the Related Art
In recent years, the necessity of converting handwritten characters, pictures, symbols, and the like into electronic data which can be handled by an information processing device has been increased. Particularly, there has been a growing demand for input means for inputting handwritten information to a computer or the like in real time without using a reader such as a scanner. As such input means, an input device which is capable of making a sheet on which dot patterns are printed transparent to visible light, disposing the transparent sheet on the front of a display device, and inputting the content directly handwritten on the transparent sheet to an information processing device has been proposed.
Since these devices suppress influence of printed matter or a display on the design or visibility, these devices are designed such that the pattern of infrared rays is recognized as data. A reading method thereof is occasionally designed such that infrared light is obliquely radiated and then the infrared light reflected by the pattern is read by a reading machine disposed right next to an infrared light irradiation unit.
As a method of preparing a pattern of infrared rays, for example, JP2008-268585A discloses a pattern printed sheet in which an invisible-ray reflective transparent pattern is printed on the surface of a substrate, an ink constituting the transparent pattern contains a material reflecting invisible rays, and the material reflecting the invisible rays is a retroreflective material.